Messages in this thread | | | Date | Tue, 28 Oct 2014 08:10:24 +0100 | From | Matthias Klein <> | Subject | Re: [PATCH v2] pinctrl: bcm2835: Start GPIO numeration at zero |
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Am 28.10.2014 um 01:00 schrieb Stephen Warren: > On 10/27/2014 05:05 PM, Matthias Klein wrote: > >> - To be in sync with the GPIO numbers in the datasheet / documentation > > I assume that's only relevant because of the second point; the GPIO > IDs in DT files already match the datasheet. > >> - For userland applications which rely on these GPIO numbers > > This isn't a scalable solution for that; this "fix" can only work for > a single GPIO controller in any one system. It'd be better for all > usage to search for the correct GPIO controller in sysfs, find the > base address of that, and then add on the controller-relative GPIO ID. > That way, the same approach is taken irrespective of which GPIO > controller is in use, and there are no special cases. > > Perhaps this could be simplified (removing the need to adding > base+offset to get the Linux ID) if the GPIO core exported a > per-controller directory in sysfs for GPIO manipulation (the files in > which used controller-relative numbering), rather than having a single > directory using Linux-internal global GPIO numbering; something like > /sys/class/gpio/gpio@7e200000/export which uses ID 0..N vs. > /sys/class/gpio/export which uses IDs X..X+N where X is arbitary. Would you accept a patch which implements the "gpio-base" property into the device tree for pinctrl-bcm2835?
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